void PETSC_STDCALL isdifference_(IS is1,IS is2,IS *isout, int *__ierr ){
*__ierr = ISDifference(
(IS)PetscToPointer((is1) ),
(IS)PetscToPointer((is2) ),isout);
}
int main(int argc,char **argv)
{
Mat M,Mo,C,K,Ko,A[3]; /* problem matrices */
PEP pep; /* polynomial eigenproblem solver context */
IS isf,isbc,is;
PetscInt n=200,nele,Istart,Iend,i,j,mloc,nloc,bc[2];
PetscReal width=0.05,height=0.005,glength=1.0,dlen,EI,area,rho;
PetscScalar K1[4],K2[4],K2t[4],K3[4],M1[4],M2[4],M2t[4],M3[4],damp=5.0;
PetscBool terse;
PetscErrorCode ierr;
PetscLogDouble time1,time2;
SlepcInitialize(&argc,&argv,(char*)0,help);
ierr = PetscOptionsGetInt(NULL,"-n",&n,NULL);CHKERRQ(ierr);
nele = n/2;
n = 2*nele;
ierr = PetscPrintf(PETSC_COMM_WORLD,"\nSimply supported beam damped in the middle, n=%D (nele=%D)\n\n",n,nele);CHKERRQ(ierr);
dlen = glength/nele;
EI = 7e10*width*height*height*height/12.0;
area = width*height;
rho = 0.674/(area*glength);
K1[0] = 12; K1[1] = 6*dlen; K1[2] = 6*dlen; K1[3] = 4*dlen*dlen;
K2[0] = -12; K2[1] = 6*dlen; K2[2] = -6*dlen; K2[3] = 2*dlen*dlen;
K2t[0] = -12; K2t[1] = -6*dlen; K2t[2] = 6*dlen; K2t[3] = 2*dlen*dlen;
K3[0] = 12; K3[1] = -6*dlen; K3[2] = -6*dlen; K3[3] = 4*dlen*dlen;
M1[0] = 156; M1[1] = 22*dlen; M1[2] = 22*dlen; M1[3] = 4*dlen*dlen;
M2[0] = 54; M2[1] = -13*dlen; M2[2] = 13*dlen; M2[3] = -3*dlen*dlen;
M2t[0] = 54; M2t[1] = 13*dlen; M2t[2] = -13*dlen; M2t[3] = -3*dlen*dlen;
M3[0] = 156; M3[1] = -22*dlen; M3[2] = -22*dlen; M3[3] = 4*dlen*dlen;
/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Compute the matrices that define the eigensystem, (k^2*M+k*C+K)x=0
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
/* K is block-tridiagonal */
ierr = MatCreate(PETSC_COMM_WORLD,&Ko);CHKERRQ(ierr);
ierr = MatSetSizes(Ko,PETSC_DECIDE,PETSC_DECIDE,n+2,n+2);CHKERRQ(ierr);
ierr = MatSetBlockSize(Ko,2);CHKERRQ(ierr);
ierr = MatSetFromOptions(Ko);CHKERRQ(ierr);
ierr = MatSetUp(Ko);CHKERRQ(ierr);
ierr = MatGetOwnershipRange(Ko,&Istart,&Iend);CHKERRQ(ierr);
for (i=Istart/2;i<Iend/2;i++) {
if (i>0) {
j = i-1;
ierr = MatSetValuesBlocked(Ko,1,&i,1,&j,K2t,ADD_VALUES);CHKERRQ(ierr);
ierr = MatSetValuesBlocked(Ko,1,&i,1,&i,K3,ADD_VALUES);CHKERRQ(ierr);
}
if (i<nele) {
j = i+1;
ierr = MatSetValuesBlocked(Ko,1,&i,1,&j,K2,ADD_VALUES);CHKERRQ(ierr);
ierr = MatSetValuesBlocked(Ko,1,&i,1,&i,K1,ADD_VALUES);CHKERRQ(ierr);
}
}
ierr = MatAssemblyBegin(Ko,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
ierr = MatAssemblyEnd(Ko,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
ierr = MatScale(Ko,EI/(dlen*dlen*dlen));CHKERRQ(ierr);
/* M is block-tridiagonal */
ierr = MatCreate(PETSC_COMM_WORLD,&Mo);CHKERRQ(ierr);
ierr = MatSetSizes(Mo,PETSC_DECIDE,PETSC_DECIDE,n+2,n+2);CHKERRQ(ierr);
ierr = MatSetBlockSize(Mo,2);CHKERRQ(ierr);
ierr = MatSetFromOptions(Mo);CHKERRQ(ierr);
ierr = MatSetUp(Mo);CHKERRQ(ierr);
ierr = MatGetOwnershipRange(Mo,&Istart,&Iend);CHKERRQ(ierr);
for (i=Istart/2;i<Iend/2;i++) {
if (i>0) {
j = i-1;
ierr = MatSetValuesBlocked(Mo,1,&i,1,&j,M2t,ADD_VALUES);CHKERRQ(ierr);
ierr = MatSetValuesBlocked(Mo,1,&i,1,&i,M3,ADD_VALUES);CHKERRQ(ierr);
}
if (i<nele) {
j = i+1;
ierr = MatSetValuesBlocked(Mo,1,&i,1,&j,M2,ADD_VALUES);CHKERRQ(ierr);
ierr = MatSetValuesBlocked(Mo,1,&i,1,&i,M1,ADD_VALUES);CHKERRQ(ierr);
}
}
ierr = MatAssemblyBegin(Mo,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
ierr = MatAssemblyEnd(Mo,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
ierr = MatScale(Mo,rho*area*dlen/420);CHKERRQ(ierr);
/* remove rows/columns from K and M corresponding to boundary conditions */
ierr = ISCreateStride(PETSC_COMM_WORLD,Iend-Istart,Istart,1,&isf);CHKERRQ(ierr);
bc[0] = 0; bc[1] = n;
ierr = ISCreateGeneral(PETSC_COMM_SELF,2,bc,PETSC_USE_POINTER,&isbc);CHKERRQ(ierr);
ierr = ISDifference(isf,isbc,&is);CHKERRQ(ierr);
ierr = MatGetSubMatrix(Ko,is,is,MAT_INITIAL_MATRIX,&K);CHKERRQ(ierr);
ierr = MatGetSubMatrix(Mo,is,is,MAT_INITIAL_MATRIX,&M);CHKERRQ(ierr);
ierr = MatGetLocalSize(M,&mloc,&nloc);CHKERRQ(ierr);
/* C is zero except for the (nele,nele)-entry */
ierr = MatCreate(PETSC_COMM_WORLD,&C);CHKERRQ(ierr);
ierr = MatSetSizes(C,mloc,nloc,PETSC_DECIDE,PETSC_DECIDE);CHKERRQ(ierr);
ierr = MatSetFromOptions(C);CHKERRQ(ierr);
ierr = MatSetUp(C);CHKERRQ(ierr);
ierr = MatGetOwnershipRange(C,&Istart,&Iend);CHKERRQ(ierr);
if (nele-1>=Istart && nele-1<Iend) {
ierr = MatSetValue(C,nele-1,nele-1,damp,INSERT_VALUES);CHKERRQ(ierr);
}
ierr = MatAssemblyBegin(C,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
ierr = MatAssemblyEnd(C,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Create the eigensolver and solve the problem
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
ierr = PEPCreate(PETSC_COMM_WORLD,&pep);CHKERRQ(ierr);
A[0] = K; A[1] = C; A[2] = M;
ierr = PEPSetOperators(pep,3,A);CHKERRQ(ierr);
ierr = PEPSetFromOptions(pep);CHKERRQ(ierr);
ierr = PetscTime(&time1); CHKERRQ(ierr);
ierr = PEPSolve(pep);CHKERRQ(ierr);
ierr = PetscTime(&time2); CHKERRQ(ierr);
/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Display solution and clean up
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
/* show detailed info unless -terse option is given by user */
ierr = PetscOptionsHasName(NULL,"-terse",&terse);CHKERRQ(ierr);
if (terse) {
ierr = PEPErrorView(pep,PEP_ERROR_BACKWARD,NULL);CHKERRQ(ierr);
} else {
ierr = PetscViewerPushFormat(PETSC_VIEWER_STDOUT_WORLD,PETSC_VIEWER_ASCII_INFO_DETAIL);CHKERRQ(ierr);
ierr = PEPReasonView(pep,PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr);
ierr = PEPErrorView(pep,PEP_ERROR_BACKWARD,PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr);
ierr = PetscViewerPopFormat(PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr);
}
ierr = PetscPrintf(PETSC_COMM_WORLD,"Time: %g\n\n\n",time2-time1);CHKERRQ(ierr);
ierr = PEPDestroy(&pep);CHKERRQ(ierr);
ierr = ISDestroy(&isf);CHKERRQ(ierr);
ierr = ISDestroy(&isbc);CHKERRQ(ierr);
ierr = ISDestroy(&is);CHKERRQ(ierr);
ierr = MatDestroy(&M);CHKERRQ(ierr);
ierr = MatDestroy(&C);CHKERRQ(ierr);
ierr = MatDestroy(&K);CHKERRQ(ierr);
ierr = MatDestroy(&Ko);CHKERRQ(ierr);
ierr = MatDestroy(&Mo);CHKERRQ(ierr);
ierr = SlepcFinalize();CHKERRQ(ierr);
return 0;
}
